1. Field of the Invention
This invention relates to conductive polymer devices and in particular to apparatus and method for testing and detecting a fault condition in such devices.
2. Introduction to the Invention
Conductive polymer compositions exhibiting PTC behavior, and electrical devices comprising them, are well known. Reference may be made, for example, to U.S. Pat. Nos. 3,793,716, 4,177,376, 4,177,466, and 4,421,582, the disclosures of which are incorporated herein by reference.
Apparatus and method for detecting fault conditions in conductive polymer devices are known and are disclosed in commonly assigned U.S. Ser. No. 324,470 (Rhodes), now U.S. Pat. No. 4,506,259, in which a device is tested by evaluating the high frequency noise which it generates.